Abstract
The work presented here reports the initial experimentation techniques and observations of wave propagation over obstacles that vary its depth and length. The experiment investigates this relationship between some wave parameters and the incident wave frequency to characterize a simplified behaviour of long waves, this depicting its changes after they move from open ocean waters to transitional waters. The changes into these parameters could shed light on possible changes into the wave field that marine energy devices, structures and offshore marine energy platforms could face in average wave weather conditions dominated by long waves in a coastal non-uniform seabed transition. The carried experiments try to characterize some wave parameters as the wavelength, amplitude and wave velocity that are frequency dependant after the waves propagate over an abrupt obstruction; the obstruction created by the obstacles, partially blocks the wave path in a wave flume tank. The experiment tries to capture the change in the wave parameters, this observing its dependence on the incident and transmitted wave frequency. Several tested frequencies allow us to obtain the variation between the frequency (f) and the parameters (α) affected by some unknown function (β), the parameter variation is then linked to the changes into the tank obstruction as then they might be related to the changes in the obstacle main length (l) and depth (hd). The initial report looks into the relations between these parameters and the possible changes in the underwater wave field properties and also its effects on the surface. The experimentation was made in a wave flume tank, using a set of obstacles that resemble simplified-regular changes in the seabed depth; the experiments used 1st order and 2nd order waves, in deep and transitional depth waters. The tested waves resemble moderate to light swell conditions at 40m depth.